The fifth and final beta version of Firefox 3 was released on Wednesday, ahead of the updated browser's final release in June.

The new beta includes more than 750 changes from its predecessor, according to Mozilla, the maker of Firefox. The company has claimed that security, stability and web compatibility have been improved, and suggested that Firefox 3, which is based on the new Gecko 1.9 web-rendering platform, will be the fastest-ever version of the browser.

It also appears that one of the most significant issues with Firefox in recent times — its heavy memory leakage — has been fixed. Testing of Firefox 3 beta 4 by Firefox developers, as well as by independent observers, has shown that the browser's memory footprint has become smaller than that of previous versions, according to the developers. The memory footprint is now also smaller than that of competing browsers, such as Safari and Internet Explorer.

Another factor in beta 5 that should significantly increase Firefox's speed is improvements in connection parallelism. Browsers generally use two connections to the same site in order to retrieve data. Because web pages are becoming more complex, an increase in the number of connections supported by the browser should mean faster data retrieval.